Means for separating short coarse fibers from long fine fibers



May 6, 1947. R. A. FAIRBAIRN ,4

MEANS FOR SEPARATING SHOlitT CIOARSE FIBERS FROM LONG FINE FIBERSOriginal Filed Sept. 10, 1941 4 Sheets-Sheet 1 7- R; A. FAIRBAIRN2,420,036

MEANS FOR SEIARATING SHORT COARSE FIBERS FROM LONG FINE FIBERS OriginalFiled Sept. 10, 1941 -4 Sheets- Sheet 2 Jizaerziq 4 fiqZerijlia'ifimm 3%w 6* y 6, 1947- R. A. FAlRBAlRN 2,420,036

MEANS FOR SEPARATING SHORT COARSE FIBERS FROM LONG FINE FIBERS OriginalFiled Sept. 10, 1941 4 Sheets-Sheet 3 ZnVenZar zaa zz mafia-7w M y 1947.R. A. FAIRBAIRN 2,420,035

MEANS FOR SEPARATING SHORT COARSE FIBERS FROM LONG FINE FIBERS OriginalFiled Sept. 10; 1941 4 Sheets-Sheet 4 Patented May 6, 1947 MEANS FORSEPABATING SHORT COARSE FIBERS mans mom LONG m Robert A.Fairbaim,Needham, Mass. Original application September 10, 1941, SerialDivided and this application March 15, 1945, Serial No. 582,852

3 Claims.

, 1 This invention concerns the separation of the textily-useful, fineand curly down fibers from the relatively coarse, stiff, straight andbrittle beard hairs or fibers which together constitute cashmere,camel's-hair or similar fieeces.- In copending application Serial No.410,300, filed September 10, 1941, of which this is a division, there isdisclosed a novel method of and apparatus for automatically andmechanically separating the hairs from the down fibers, said separationinvolving as a step the division of the coarse hairs or fibers intoshort lengths, for example,

sideration of the following description and o! the annexed drawings, inwhich one embodiment of my apparatus is chosen for the purpose ofillustration.

In the drawings:

Fig. 1 is a plan view of a machine embodying. my invention;

Fig. 2 is an enlarged section taken on the line 2-2 of Fig. 1;

into lengths approximating inch without substantial injury to orvshortening of the down fibers as a preliminary to the actual segregationof the coarse from the fine fibers.

The principal object of the present invention is to provide a novelmethod of and apparatus for separating the useful down fibers from thefragments of beard hairs after the latter have been divided into shortlengths as 'above,suggested.

Cashmere fleece is obtained from the Cashmere Fig. 3 is asection takenon the line 3-4 of 2;

Fig. 4 is an enlarged section taken on the line 4-4 of Fig. 1; I

Fig. 5 is an enlarged partial section taken on the line 5-5; of Fig. 1';

Fig. 6 is a side elevation of that part of the apparatus which is shownin Fig. 4;

goat which is native in Tibet and Northem India. The fleece is receivedin this country in bale form and consists of a mixture of down fibers,beard fibers, dandruff, natural oil or grease and dirt. The grease anddirt are removed by.

Fig. '7 is atop plan photograph of a jumbled mass of cashmere fleece asit appears upon arrival in thiscountry prior'to the removal of dirt andgrease by scourin Fig. -8 is a top plan photograph of the web or -fil1'nof cashmere fleece produced by scouring the fleece of Fig. 6 and thenpassing it through a carding machine;

Fig. 9 is a plan view of the web or film of aligned cashmere beard anddown fibers produced by a preferred step of my method;

scouring, leaving a jumbled mass which consists I of approximately 75%by weight of down fibers, 25% beard fibers, plus dandruff. Prior tothisinvention so far as I know the beardfibers and dandruff were removed byrepeated carding and combing and also, in Japan, beard fibers by hand.During each carding and each combing operation many of the down fiberscling to the beard fibers and are removed with them so that a cashmeretop (long down fibers more or less freed from beard fibers) isvery-expensive dueboth to the many carding and combing operationsnecessary for removal of the beard fibers and to the waste of downfibers which are removed with the beard fibers. Furthermore, a cashmeretop made by that process still contains some beard fibers, thepercentage often being.

by picking out the as high as 10% by weight. When free cashmere noils(short down fibers substantially free from beard fibers) are produced bycarding and combing, it is necessary to set the combs very closely inorder to comb the down fibers out of the beard fibers,- and this causesthe down fibers to be broken up into very short lengths of the order ofabout 'a.n inch, and the value of such fibers is quite limited.

Further objects will be apparent from a con- Fig-10 is an enlargedsection taken on the line ill-moi Fig.9;

Fig. '11 is a top plan photograph illustrating the appearance of thefibers of Fig. 9 after the beard fibers have been cut into shortsegments during another step of my method;

Fig. 12 is a top plan photograph illustrating the appearance of thecashmere-down fibers after,

the cut segments of beard fibers and dandruff have been removed; and

Fig. 13 is a top plan photograph showing-cut segments of beard fibersand dandruff as they appear after removal from the down fibers.

The cross section of cashmere down fibers is quite uniformly circular,the average diameter is, about 15 microns, and the length-varies fromabout 1% to about 3% inches. The cross section of cashmere beard fibersvaries from circular to ribbon-like, the diameter or thickness variesfrom about 30 to about 150 microns, the average diameter or thickness isabout microns and the length varies from about 1 inches to about 5inches. The beard fibers are-not only thicker than the down fibers, butthey are more brittle. The down fibers are normally very soft and verycrinkly, whereas the beard fibers are much stifier and straighter. Thesecharacteristics are illusand 10) in which the beard hairs or fibers areI substantially only one fiber deep and are aligned to extendsubstantially in the same direction; supporting this web or film on ahard surface;

'then causing spaced cutting devices to engage the beard fibers to cutthem into short segments without substantially cutting the down fibers(see Fig. 11) and thereafter separating the substantially uncut downfibers (Fig. 12) from the cut segments of the beard fibers and thedandruff (Fig. 13).

The jumbled mass of cashmere fieece (shown in Fig. 7) is first subjectedto a scouring operation, using soap and water, to thereby remove thegrease and dirt. After drying, the resultant mass of beard fibers, downfibers and dandruff is passed through a carding machine (not shown)which is preferably provided with metallic clothing. This produces athin web or film H which is about five feet wide and in which the fibersare not aligned, but cross and recross each other, as shown in Fig. 8.This web is fed from the carding machine to a conveyor belt (Fig. 2)which continuously advances the web from the carding machine to the biteof the rolls l8 and 20. The conveyor belt passes around the roll l6which is mounted for rotation in suitable bearings supported by theframe members 30. The speed of this belt may be about two feet persecond.

The shafts of the rolls 8 and I9 are mounted for rotation each insuitable bearings located adjacent to the ends of each roll andsupported by the frame members 30. The surface of the roll l8 engagesboth the surface of the roll 20 and the surface of the roll l9, but thesurface of the roll I9 is spaced from the surface of the roll 20, asshown in Fig. 2. Each of the rolls i8 and I9 is provided with a rubbercovering, and each is rotated in a counterclockwise direction (lookingat Fig. 2) by suitable connections with the driven shaft 3|, the roll I8being rotated at a surface speed of about two feet per second, and theroll l9 at a greater surface speed which may be of the order of six feetper second,

The shaft 32 of the roll 20 is mounted for rotation in suitable bearingblocks 33 which are located adjacent to each of its ends and aresupported by the frame members 30 and 34. One end of the shaft 32 isprovided with a pulley 35 which may, be driven bya belt (not shown), thebelt in turn being driven from any suitable source of power. The otherend of this shaft 32 is provided with a gear (not shown) which mesheswith the gear 36 (Fig. 1) secured to the shaft 31 of the upper roll 2|.These rolls 20 and 2| are driven at a greater surface speed than that ofthe roll I8 and their surface speed may be about six feet per second,the roll 20 being rotated in a clockwise direction and the roll 2| in acounterclockwise direction (looking at Fig. 2).

The shaft 31 of the roll 2| is mounted for rotation in bearing blocks 38which are located ad- Jacent to its ends. These blocks 38 are mountedfor vertical sliding movement along ways provided in the frame members30. The blocks are urged upwardly by springs 39 (Fig. 2), the lower endof each spring being retained in a recess provided in the top of theblock 33, and the upper end of each spring being retained in a recessprovided in the bottom of the block 38. These springs 39 are strongenough to support both the weight of -the blocks 38 and that of the roll2|. These springs 39 would thus hold the surface of the roll 2| out ofcontact with the surface of the roll 20 unless an additional downwardforce is applied of sufficient intensity to further cOmpress thesestrong springs.

An adjusting bolt 4| is provided for each bearing block 38. The upperportion of the shank of each bolt 4| is provided with screw threads, andthese screw threads engage the threads of an interiorly threadedaperture which extends through a steel block 44 which is welded to theframe cross member 40. The lower end of the shank of each bolt is ofreduced diameter and is provided with screw threads. These threadsengage the threads of an interiorly threaded aperture which is providedin a steel block 42, said block being secured to the top of the bearingblock 38. Fewer screw threads per linear inch are provided On the upperportion of the bolt shank than on the lower reduced portion thereof, forexample l2 threads per inch on the former portion and I3 on the latterportion, and both sets of threads are right-hand or both sets lefthand.In such an arrangement, one complete turn of the bolt 4! lowers orraises the associated bearing /10 of an inch. Turning the two bolts 4|thus serves very slowly to force the bearing blocks 38 downwardlyagainst the upward pressure of the springs 39 and thereby to delicatelyadjust the spacing of the peripheral surface of the roll 2| from that ofthe roll 20.

Interiorly threaded rings or collars 45 are screwed to exteriorlythreaded depressed portions at opposite endsof the roll 2|, theperipheral 'surfaces of the collars being substantially fiush with thesurface. of the roll. A series of pins 46 is secured to each collar 45.Steel wire 41, having a diameter of about mo of an inch, is loopedaround a pin 46, wound once around the surface of the roll 2|, and thenlooped around a pin 46 directly opposite the first pin but located atthe opposite end of the roll. The roll is thus continuously wound with asingle strand of steel wire. Each length of the wire is parallel to theadjacent length and is spaced about of an inch therefrom. The collars 45may be screwed outwardly with respect to the respective ends of the rollto thereby pull the wire as tightly against the surface of the roll asdesired and after such adjustment the wire may be anchored to the pinsby soldering. Each collar 45 may be secured in adjusted position by setscrews (not shown) which pass through interiorly threaded apertures inthe end of the collar and engage the adjacent and of the roll 2|.

The surface of each of the metal rolls 20 and 2| is ground with extremeaccuracy both longitudinally and concentric with the bearing surface ofits shaft and this causes the surface of the wires 41 to exert a uniformpressure against the surface of the roll 20 throughout the length of thesurface of the roll and during each complete revolution of the rolls 20and 2|. Thus the surface of the upper roll 2| is provided with a seriesof closely spaced steel wires 41 which rotate in unison with the rolland which engage the surface of the lower roll 20 with a uniformpressure, the amount of which may be delicately varied by turning thebolts 4|.

A moistening reservoir 50 is supported on a of the roll 20. The lengthof the reservoir 50 'and of the fibrous material 53 is substantially thesame as that of the surface of the roll 20, so that the fibrous materialengages the entire length of the surface of said roll. The fibrous by aseries of bolts 55 which passmaterial preferably is closely compacted,(18-.

greased, wool felt and it transfers the water or other moistening agentfrom the reservoir 50 to the surface of the roll to continuously applyto said surface a thin coating or film of moisture. The characteristicsof this coating may be controlled by adjustment of the set screws 51 toincrease or decrease the pressure of the fibrous material against thesurface of the roll and by adjustment of the bolts 55- to increase'ordecrease the pressure of the crossbar .56 against the surface of thefibrous material.

A rubber-covered roll 22 is mounted on a shaft which is mounted forrotation in suitable bear-v ings supported by the frame members 30. Theroll 22 is rotated in a clockwise direction .(looking at Fig. 2) bysuitable connections with a drive shaft 86, the surface speed ofrotation of the roll being substantially the same as that of the roll20.

A pair of metallic conduits 60 extends from a point adjacent to thesurface of the roll 22 to the fan housings BI. vided with a fan 62which, upon rotation, is adapted to create suction in the associatedconduit 60 and positive pressure in the associated housing outlet 63.,The housing outlet member 63 is connected by the member 64 with the endof a length of glass tubing I0. The opposite end of the glass tubing 10is provided with a cap I00 (Figs. 1, 4 and 6) the end portion of whichis of greater diameter than the body portion so as to provide acircumferentially extending channel IN. A discharge tube I02 leadsdownwardly from the lower portion of this channel A branch tube 1|,arranged at substantially right angles to the tube I0, has one endcommunicating with the interior of the tube 10 at a point adjacent tothe cap I00. The opposite end of this tube II is also provided with acap I00 similar to"the cap just described. The tube II is providedwith'a branch 12 having its axis disposed substantially at right anglesto that of" the tube II and communicating with the tube II just inadvance of the capped end of thelatter, the tubes 10 and II being thefirst of a series constituting a system of branched tubes which, as hereillustrated, includes the tubular branches I3, 14, I5 and I6, it beingunderstood that a greater or lesser number of branches may be employedin accordance with circumstances and in particular with reference to thetype of fiber being handled and the degree of separation de- Each fanhousing is pro-.

preceding tube, it is contemplated that they may be so arranged as tocause the air to make an even more abrupt change in .direction ifdesired. It is further to be noted that each branch extends beyond itsjunction with the next succeeding branch of the series so as to providea dead air chamber in direct axial alignment'with each branch passage,such dead air chamber in each instance having a terminal cap I00 withits annular channel I0! from which leads a discharge tube I02.

A series of closure disks orvalves 8| is provided, one for each of thetubes I02 and each having one of its faces located adjacent to .andnormally closing the lower end of the corresponding tube I02; Each ofthese disks is provided .with an orifice or aperture '82 (Fig. 4) whichis of substantially the same diameter as the opening at the lower end ofthe corresponding tube I02. Each disk is mounted on a shaft 83 which iscon tinuously rotated from any available source of power so that theorifice 82 of each disk intermittently registers with the opening of thecorresponding tube I02, thereby periodically to afford communicationbetween the interior of the tube 1 02 and the interior of an associatedtube 85, coaxial with the tube I02 and having its open end close to theopposite radial face of the disk. The several tubes 85 lead to a maincollection trunk 86.

A tube 1,1 is connected to the last branch 18 of the system and providescommunication between the interior of this last branch 16 and a chamber80 provided in an elongate casing (Figs. 1 and 5).

The floor of the chamber 90 is provided with a series of parallel slotswhich receive the upper portions of fiber entraining disks 9| havingrough sired. Itis to be noted that the several branches 4 diverge fromeach other at a substantially right angle as here illustrated so thatthe air current, in passing from one branch to the next of he series, iscompelled to change-its direction very abruptly. While as here shown theseveral branches diverge each at a right angle from the edges andpreferably having rough radial surfaces. For example, these disks mayconsist of stiif wire screen fabric. The disks 8| are secured to shafts92 which are arranged outside the casing and which are rotated in acounterclockwise direction as viewed in Fig. 5.

Scrapers 93 located outside of the casing constitute means for removingthe fibers which cling to the edge of each of the disks, it beingunderstood that a scraper 93 is arranged at each side of each disk. Thefibers so removed from the disks drop onto a conveyor belt 94.

In operation, the web or film I4 consisting of dandruff and crossedbeard and down fibers (Fig. 8) is advanced by the belt I5 to the bite ofthe rolls I8 and 20 (Fig. 2), the speed of the web being about two feetper second, the surface speed. of the roll I8 being about the same asthe speed of the web and the surface speed of the roll 20 being greaterthan the surface speed of the roll I8. The surface of the roll 20 iscontinuously coated with moisture b the fibrous material 58,

and this moisture tends to retain the fibers in' the faster moving roll20 against the surface of said freed end portion of the fiber causes itto be rearranged on the surface of the roll 20 and to extend along saidsurface in a direction substantially at right angles from the line ofthe bite of the rolls I8 and 20 where the lower part of the fiber isstill engaged by said bite. This aligning action is caused by thetendency of the freed end portion of the fiber to seek the position ofleast resistance on the surface of the rapidly moving roll 20 while thelower part of the fiber is still engaged by the roll l8. Each of thefibers is thus progressively aligned as it progressively advancesthrough said bite so that before the fibers pass through the bite of therolls 2| and 20 they have been rearranged in a web or film of athickness approximating the average diameter of the beard fibers and inwhich they are aligned to extend along the surface of the roll 20substantially in the same direction. This web or film of aligned fibersis shown diagrammatically in Figs. 9 and 10,-the arrow at the top ofFig. 9 indicating the direction of movement of the surface of the roll20, the beard fibers being indicated by the heavy lines and the downfibers by the lighter lines.

The moisture on the surface of the roll 26 serves to keep the fibers inengagement with the surface of the roll 20 both when they'are beingaligned and after the alignment has been completed. Without the use ofmoisture the crinkly down fibers tend to separate or free themselvesfrom the surfaces of the roll 20 so that alignment is less complete andso that they do not as readily remain in such realigned arrangementuntil they enter the bite of the rolls 2| and 20.

The function of the rolls I9 is to remove from the surface of the rolll8 any fibers which adhere thereto and to direct or return such fibersto the surface of the roll 20.

As this web or film ofaligned fibers progressively passes between thebite of the rolls 20 and 2| (see Figs. 9 and 10) the spaced wires 41progressively engage each beard fiber at spaced intervals, and thecurved surface of the wire (a radius of about 200 of an inch) cutsthrough each beardfiber to progressively separate it into short segmentsof about /s of an inch in length. When the pressure of the wire againstthe surface of the lower roll is properly adjusted the beard fibers arethus cut into short segments but the down fibers are substantiallyuncut. I believe this result is due to the fact that the beard fibersare thicker and more brittle than the down fibers so that by accurateadjustment of the cutting pressure of the wires their pressure on thedown fibers is insufficient to sever them, whereas their pressure on thebeard fibers is greater and is sufficient to sever them.

The bite of the rolls 2| and 22 is preferably located slightly more than3 inches from the bite of the rolls i8 and 20 so that-down fibers willnot be gripped at the same time both by the bite of the rolls l8 and 20and by the wires 41 to thereby break the down fibers. By reducing thepressure at the bite of the rolls l8 and 2|], however, the machine maybesatisfactorily operated with a shorter distance between said bites.

Fig. 11 illustrates the material as removed after passing the bite ofthe rolls 2'9 and 2|, the material then consisting of cut segments ofbeard fibers, substantially uncut down fibers and pieces of dandruff. Itwill be observed that the length of the cut segments of beard fibersvaries. This is probably due to the fact that the diameter or thicknessof beard fibers varies so that the pressure exerted by the wires isinsufiicient to sever the fiber in some localities, whereas it issufficient to sever the fiber at most localities. Some of the downfibers may be cut, but the majority of them are uncut and after theshort cut segments of beard fibers have been removed the resultant massconsisting of substantially uncut down fibers is of great value in themanufacture of yarn and fabrics. Even if all of the down fibers are outonce or twice (which result may be accomplished by passing the card webshown in Fig. 8 directly from the carding machine through the bite ofthe rolls 2| and 2') the resultant down fibers are long enough to makean end product which is acceptable for some purposes.

The suction which is created by the fans at the mouth of the conduits 60draws the material emergin from the bite of the rolls 2| and 20.1nto

the conduits 60. Any of this material which continues to adhere to thesurface of the roll 20 is removed therefrom by the roll 22 and thesuction at the mouth of the conduits 60 removes such material from thesurface of the roll 22 as well as any material which adheres to thesurface of the roll 2| and draws said material into the conduits 60.

.The mass of down fibers, cut beard fibers, and dandrufi then passes tothe fan housing 8| where it is agitated by the fan 62 and is thereafterblown out through the outlet 63, the connecting member 64, and into thetube Hi. When the fibers reach the entrance to the tube 1| many of thelighter weight and longer down fibers are forced around the corner intothe tube 1| whereas many of the shorter segments of the beard fiberspass beyond the entrance to the tube H and into the cap I00. The exitopening of the tube I02 is normally closed so the segments of beardfibers collect in said tube. Some dandruff and some of the down fibersalso pass beyond the entrance to the tube 1|, the adjacent portion ofthe tube 10 and into the cap I00. The eddy air currents which are set upin the cap agitate these down fibers and continuously force them back tothe entrance to the tube H, and thence into the tube I I. These sameeddy currents tend to remove the dandruff and the beard fiber segmentswhich adhere to the down fibers, which thus pass to the extensionportions of the tube 10, said dandruff and beard fiber segments beinthrown outwardly into the channel I ill from which they fall to the tubeI02.

When the opening 82 in the disk 8| periodically registers with the exitend of the tube I02, the beard fiber segments and the dandruff, whichhave collected at the end of said tube, are forced out through theopening 82 into the tube 85 and thence into the collection tube 86. Thiswaste product is illustrated in Fig. 13.

The ,cap I00 and the portion of the tube III which extends beyond theentrance to the tube 1| form what is referred to in the claims as asubstantially dead air chamber. This phraseology is used notwithstandingthe eddy air currents which are present in that part of the apparatusbecause the main air current set up by the fan 62 is directed towardsaid dead air chamber but since the exit end of the tube N12 is normallyclosed the greatest part of said main air current does not pass intosaid dead air chamber and is forced to pass around the corner into thetube Each down fiber is much longer than each cut section of beard fiberand has substantially the same weight, and consequently the main aircurrent, as it turns the corner into the tube 1|,

is more easily able to change the direction of the longer down fibersthan of the shorter section of beard fibers. It is for this reason thatmany of the beard fiber sections pass into the substantially dead airchamber, whereas most of the down 9 fibers do not enter it at all butpass directly around the corner into the tube ll.

Not all of the beard fiber segments and dandruff are removed in thefirst substantially dead air space of the tube 10, and the down fibers,together with the remaining dandrufi and beard fiber segmentscontinuously pass along the tube H in which the same process of removaltakes place as that which has been described above with respect to thetube 10. A sufficient number of branch tubes, similar to the tubes 10and II, is provided to completely remove the down fibers from theundesirable beard fiber segments and dandrufi, seven such tubes beingillustrated as associated with each of the two fan housings Si in theembodiment shown in the drawings.

The down fibers which pass from the last of these tubes 16 into the tube11 are illustrated in Fig. 12 and they are satisfactory for use in themanufacture of yarn. However, they present a somewhat tangled anddisorderly appearance because of the agitation to which they have beensubmitted by the air currents in the series of tubes. The rotating disks9| tend to untangle the down fibers and to rearrange them so that theypresent a more attractive appearance for marketing. As the fibers areblown from the tube 11 into the chamber 90, they catch intermediatetheir ends on the edge of the rotating disks 9| and are thus removedfrom the mass. The disks carry the fibers downwardly and some of themfall from the edge of the disks to the conveyor belt 94, whereas thosewhich continue to adhere to the disks are removed by the scrapers 93from which they fall to the surface of the belt 94. The end product iscollected from the surface of the belt 94 and consists of substantiallyuncut down fibers which are substantially free from beard fibers anddandrufi.

Those aspects of the method and apparatus which relate solely toreducing the thickness of the carded web or film, to parailelizing thebeard and down fibers or to advancing the resultant web or film areclaimed in my copending continuation in part application, Serial No.662,240, filed April 15, 1946. 1

I claim:

1. Textile apparatus for use in the separation of relatively long andfine down fibers from short lengths of beard hair intermingledtherewith, the apparatus comprising separating means comprising a seriesof passages each branching from the preceding passage and each extendingbeyond its junction with the next following passage to provide a deadair chamber, each dead air chamber having an exit opening, meansnormally closing each exit opening, means operative at regular intervalsto open each exit opening, and pneumatic means operative to withdrawcollected material from each dead air chamber when the exit opening isopen.

2. Textile apparatus for use in the separation of fibers oi difierentdiameters, the coarser fibers being much shorter than the-finer fibers,the apparatus comprising separating means to which the mingled fiber isdelivered and comprising a series of passages each branching from the,next preceding passage and each extending beyond its junction with thenext following passage thereby to define a dead air chamber, each deadair chamber having an exit opening, rotary disks each so disposed thatone face thereof normally closes one of the exit openings, each diskhaving an aperture therethrough registrable with the corresponding exitopening, and means operative to turn the disks thereby at intervals toregister the apertures with said exit openings. Y

3. Textile apparatus for use in the separation of intermingledrelatively long and fine down fibers and short lengths of coarse fiber,the apparatus comprising separating means to which the mingled fine andcoarse fiber is delivered, said separating means including a system ofconnected branch passages each terminating in a dead air chamber, theseveral branches being disposed each at substantially right angles tothe next. jmeans providing an inlet to said system, means providing anoutlet to said system, means for creating a fiber-carrying air currentfrom end to end of said system, means affording communication with theatmosphere at the inlet end.oi said system and means aflfordingcommunication with the atmosphere at the outlet end oi said system, saidsystem being free from communication with the atmosphere except at saidinlet and outlet ends.

ROBERT A. FAIRBAIRN.

. more crran The following references are of record in the file-oi thispatent; v I

rmrran s'ra'rms ra'rnm's Number Name Date 2,100,112 Taylor NOV. 28,1937' 837,205 Elam NOV. 27, 1906 233,847 Groom Nov. 2, 1880 661,166 BoydNov. 6, 1900 466,685 7 Hodnett et a1 Jan. 5, 1892 661,749 Sullivan NOV.13, 1900 636,164 McCormick Oct. 31, 1899 460,078. Barnard Sept. 22, 1891821,819 Neumann May-29, 1906 Morscher apr. 18, 1912

